Method for Providing Z-Axes Connections in Printed Circuit Boards Having Homogeneous Organic Dielectrics
Original Publication Date: 1997-Apr-01
Included in the Prior Art Database: 2005-Apr-01
Buth, M: AUTHOR [+5]
Disclosed is a two-step method for providing Z-connections for plated-through holes or blind vias in printed circuit boards.
Method for Providing Z-Axes Connections in Printed
Having Homogeneous Organic Dielectrics
a two-step method for providing Z-connections for
plated-through holes or blind vias in printed circuit boards.
of today's printed circuit boards are
manufactured using methods like drilling or plasma etching.
Mechanical drilling can be used down to approximately 100 &mu.m; for
the manufacture of smaller holes, the cost for the drills will be too
high if they can be manufactured at all. Plasma techniques do have
problems concerning hole geometry and repetition.
new process sequence is proposed for creating the
Z-connections in printed circuit boards. All greater and relatively
noncritical holes or vias are manufactured using wet-chemical methods
and all small holes or vias are created by laser methods.
The general sequence is as follows:
o First step
1. mechanical or, if necessary, optical adjustment
2. lithographical structuring and wet-chemical etching of
- great vias or holes (> 60-75 &mu.m)
- exposure of optical adjustment marks in the circuit
o Second step
1. optical adjustment
2. lithographic structuring and laser etching of the small
vias or holes (< 60 &mu.m)
In the following, an example for wet-etching vias in
of printed cir...